Netgear WG602 problems

I have a netgear dg834 wireless router and a netgear wg602 wireless access point. Router is attached to a desktop in the office, AP next door via long (30m) cat5e cable. Router is fine, AP won't connect but will connect on the short cable supplied with it. This is no good as I need to use it next door. Netgear advise max cable length is 100m Cable has been checked for polarity and connection and jacks and is fine. I keep getting "signal strength good, limited or no connectivity" zonealarm firewall has been disabled, SSIDs are identical, security is disabled on both. All the correct lights on both router and AP are lit.
Any ideas anyone?

simon01656